# 91

## 91 is an odd composite number composed of two prime numbers multiplied together.

What does the number 91 look like?

This visualization shows the relationship between its 2 prime factors (large circles) and 4 divisors.

91 is an odd composite number. It is composed of two distinct prime numbers multiplied together. It has a total of four divisors.

## Prime factorization of 91:

### 7 × 13

See below for interesting mathematical facts about the number 91 from the Numbermatics database.

### Names of 91

• Cardinal: 91 can be written as Ninety-one.

### Scientific notation

• Scientific notation: 9.1 × 101

### Factors of 91

• Number of distinct prime factors ω(n): 2
• Total number of prime factors Ω(n): 2
• Sum of prime factors: 20

### Divisors of 91

• Number of divisors d(n): 4
• Complete list of divisors:
• Sum of all divisors σ(n): 112
• Sum of proper divisors (its aliquot sum) s(n): 21
• 91 is a deficient number, because the sum of its proper divisors (21) is less than itself. Its deficiency is 70

### Bases of 91

• Binary: 10110112
• Base-36: 2J

### Squares and roots of 91

• 91 squared (912) is 8281
• 91 cubed (913) is 753571
• The square root of 91 is 9.5393920141
• The cube root of 91 is 4.4979414453

### Scales and comparisons

How big is 91?
• 91 seconds is equal to 1 minute, 31 seconds.
• To count from 1 to 91 would take you about forty-five seconds.

This is a very rough estimate, based on a speaking rate of half a second every third order of magnitude. If you speak quickly, you could probably say any randomly-chosen number between one and a thousand in around half a second. Very big numbers obviously take longer to say, so we add half a second for every extra x1000. (We do not count involuntary pauses, bathroom breaks or the necessity of sleep in our calculation!)

• A cube with a volume of 91 cubic inches would be around 0.4 feet tall.

### Recreational maths with 91

• 91 backwards is 19
• The number of decimal digits it has is: 2
• The sum of 91's digits is 10
• More coming soon!